Space-confined carbonization of wood cellular structure rendered an all-in-one solar-driven evaporator for efficient water desalination and evaporative power generation

With natural hierarchical porous and anisotropic cellular structure, wood yields a great opportunity for solar-driven water desalination but is limited in interfacial evaporation efficiency due to its inherent low photo-thermal conversion. Although the photothermal materials decoration and the high-temperature carbonization have been proposed, these methods often lead to poor interfacial compatibility and thermal management. Herein, a space-confined carbonization strategy of wood cellular structure was developed to construct an all-in-one solar-driven evaporator for efficient water desalination and evaporative power generation. The gradient carbonization of cellular structure caused by immersed wood into concentrated H2SO4 endows wood surface with improved photothermal conversion efficiency (91.6 %), and the interior cellular structure with natural hydrophilic (hemi)cellulose enables rapid water transportation. As a result, the space-confined carbonized wood exhibits high evaporation performance, with the evaporation rate up to 2.1 kg m-2 h-1 under 1 sun. The concentration difference of ions caused by water evaporation can also achieve power generation, with the timing current and voltage up to 34 mA and 1187 mV, respectively. In addition, the H2SO4 is reusable without affecting the evaporation stability. The developed space-confined carbonized wood also demonstrates good adaptability to various water environment. This feasible space-confined carbonization strategy provides a new sight to construct all-in-one wood-based solar-driven evaporators for improving the water desalination and evaporative power generation performance.